Context-aware Computing Research Articles

Information at a glance [augmented reality user interfaces

What if we could visualize and interact with information directly in the context of our surroundings? Our research group is exploring how augmented reality (AR) could someday make this possible. AR integrates a complementary virtual world with the physical world-for example, by using head-tracked see-through head-worn displays to overlay graphics on what we see. Instead of looking back and forth between the real world and a PDA, we look directly at the real world and the virtual information overlaid on it. At the heart of this approach is context-aware computing, computing systems that are sensitive to the context in which they operate, ranging from human relationships to physical location. For example, information might be tied to specific locations within a global, Earth-centered, coordinate system. How can we design effective mobile AR user interfaces? We've been trying to answer this question in part by developing experimental AR research prototypes. In AR, as in work on information visualization using desktop technologies, the amount of information available can far exceed what a system can legibly display at a given time, necessitating information filtering. Julier et al. (2000) have developed information filtering techniques for AR that depend on the user's goals, object importance, and proximity. We assume that a system can accomplish information filtering of this sort and that our system is displaying everything it should.

E-graffiti: evaluating real-world use of a context-aware system

Much of the previous research in context-aware computing has sought to find a workable definition of context and to develop systems that could detect and interpret contextual characteristics of an user environment. However, less time has been spent studying the usability of these types of systems. This was the goal of our project. E-graffiti is a context-aware application that detects the user's location on a college campus and displays text notes to the user based on their location. Additionally, it allows them to create notes that they can associate with a specific location. We released E-graffiti to 57 students who were using laptops that could access the campus wireless network. Their use of E-graffiti was logged in a remote database and they were also required to fill out a questionnaire towards the end of the semester. The lessons learned from the evaluation of E-graffiti point to themes other designers of ubiquitous and context-aware applications may need to address in designing their own systems. Some of the issues that emerged in the evaluation stage included difficulties with a misleading conceptual model, lack of use due to the reliance on explicit user input, the need for a highly relevant contextual focus, and the potential benefits of rapid, ongoing prototype development in tandem with user evaluation.

Privacy in Context

Context-aware computing offers the promise of significant user gains-the ability for systems to adapt more readily to user needs, models, and goals. Dey, Abowd, and Salber (2001 [this special issue]) present a masterful step toward understanding context-aware applications. We examine Dey et al. in the light of privacy issues-that is, individuals' control over their personal data-to highlight some of the thorny issues in context-aware computing that will be upon us soon. We argue that privacy in context-aware computing, especially those with perceptually aware environments, will be quite complex. Indeed, privacy forms a co-design space between the social, the technical, and the regulatory. We recognize that Dey et al. is a necessary first step in examining important software engineering concerns, but future research will need to consider how regulatory and technical solutions might be co-designed to form a public good.

Introduction to This Special Issue on Context-Aware Computing

Pervasive Computing is a term for the strongly emerging trend toward: --Numerous, casually accessible, often invisible computing devices. --Frequently mobile or embedded in the environment. --Connected to an increasingly ubiquitous network infrastructure composed of a wired core and wireless edges.

An Infrastructure Approach to Context-Aware Computing

The Context Toolkit (Dey, Abowd, and Salber, 2001 [this special issue]) is only one of many possible architectures for supporting context-aware applications. In this essay, we look at the tradeoffs involved with a service infrastructure approach to context-aware computing. We describe the advantages that a service infrastructure for context awareness has over other approaches, outline some of the core technical challenges that must be addressed before such an infrastructure can be built, and point out promising research directions for overcoming these challenges.

A Conceptual Framework and a Toolkit for Supporting the Rapid Prototyping of Context-Aware Applications

Computing devices and applications are now used beyond the desktop, in diverse environments, and this trend toward ubiquitous computing is accelerating. One challenge that remains in this emerging research field is the ability to enhance the behavior of any application by informing it of the context of its use. By context, we refer to any information that characterizes a situation related to the interaction between humans, applications, and the surrounding environment. Context-aware applications promise richer and easier interaction, but the current state of research in this field is still far removed from that vision. This is due to 3 main problems: (a) the notion of context is still ill defined, (b) there is a lack of conceptual models and methods to help drive the design of context-aware applications, and (c) no tools are available to jump-start the development of context-aware applications. In this anchor article, we address these 3 problems in turn. We first define context, identify categories of contextual information, and characterize context-aware application behavior. Though the full impact of context-aware computing requires understanding very subtle and high-level notions of context, we are focusing our efforts on the pieces of context that can be inferred automatically from sensors in a physical environment. We then present a conceptual framework that separates the acquisition and representation of context from the delivery and reaction to context by a context-aware application. We have built a toolkit, the Context Toolkit, that instantiates this conceptual framework and supports the rapid development of a rich space of context-aware applications. We illustrate the usefulness of the conceptual framework by describing a number of context-aware applications that have been prototyped using the Context Toolkit. We also demonstrate how such a framework can support the investigation of important research challenges in the area of context-aware computing.

The Context of Work

The question of how to conceive and represent the context of work is explored from the theoretical perspective of distributed cognition. It is argued that to understand the office work context we need to go beyond tracking superficial physical attributes such as who or what is where and when and consider the state of digital resources, people's concepts, task state, social relations, and the local work culture, to name a few. In analyzing an office more deeply, three concepts are especially helpful: entry points, action landscapes, and coordinating mechanisms. An entry point is a structure or cue that represents an invitation to enter an information space or office task. An activity landscape is part mental construct and part physical; it is the space users interactively construct out of the resources they find when trying to accomplish a task. A coordinating mechanism is an artifact, such as a schedule or clock, or an environmental structure such as the layout of papers to be signed, which helps a user manage the complexity of his task. Using these three concepts we can abstract away from many of the surface attributes of work context and define the deep structure of a setting-the invariant structure that many office settings share. A long-term challenge for context-aware computing is to operationalize these analytic concepts.

Toward context-aware computing: experiences and lessons

To minimize distractions, a pervasive-computing environment must be context-aware. The authors define an activity-attention framework for context-aware computing, discuss the spatial and temporal aspects of applications they developed, and introduce a pervasive-computing architecture.

Situated Interaction and Context-Aware Computing

Introduction to a special issue of the journal Personal and Ubiquitous Computing that provides a comprehensive overview of current ubiquitous computing research in the fields of situated interaction and context-aware computing.

Context-awareness in wearable and ubiquitous computing

A common focus shared by researchers in mobile, ubiquitous and wearable computing is the attempt to break away from the traditional desktop computing paradigm. Computational services need to become as mobile as their users. Whether that service mobility is achieved by equipping the user with computational power or by instrumenting the environment, all services need to be extended to take advantage of the constantly changing context in which they are accessed. This paper will report on work carried out by the Future Computing Environments Group at Georgia Tech to provide infrastructure for context-aware computing. We will describe some of the fundamental issues involved in contextaware computing, solutions we have generated to provide a flexible infrastructure and several applications that take advantage of context awareness to allow freedom from traditional desktop computing.

Disseminating active map information to mobile hosts

The article describes an active map service (AMS) that supports context-aware computing by providing clients with information about located-objects and how those objects change over time. The authors focus on the communication issues of disseminating information from an active map server to its clients, and in particular, address how to deal with various overload situations that can occur. Simple unicast callbacks to interested clients work well enough if only a few located-objects are moving at any given time and only a few clients wish to know about any given move. However, if many people are moving about in the same region and many clients are interested in their motion, then the AMS may experience overload due to the quadratic nature of the communications involved. This overload affects both the server as well as any slow communications links being used. Mobile distributed computing enables users to interact with many different mobile and stationary computers over the course of the day. Navigating a mobile environment can be aided by active maps that describe the location and characteristics of objects within some region as they change over time.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>